It's a bit confusing because, at the much larger Summer Olympics, athletes often get medals immediately after their event. A nighttime ceremony during the Summer Games would be long and chaotic. Hosting a nightly medal ceremony is more manageable at the Winter Games. (You can watch it nightly on the Olympic Channel.)
In part, the stuffed animals replace flowers, which had long been given out on the podium. Victory ceremony hosts will not be giving anyone flowers in PyeongChang. Athletes just get the animals to start, each of which is adorned with a gold, silver, or bronze hat and a paper flower called an uhsahwa. In a small way, the tradition of flowers remains alive with the dolls. Additionally, the uhsahwa holds historical significance for the host country. According to the host website, the uhsahwa is "a paper flower that was bestowed to those who passed national exams during the Joseon Dynasty (1392-1910)."